In September 2016, a bunch of Super NES (and other Nintendo system) prototypes were listed on Ebay by seller jossan. The seller got these prototypes from someone who did game testing for the company that distributed Nintendo games in Norway, called Unsaco. From the auction:

I am currently listing an impressive lot of prototypes, all which come from the collection of two brothers who worked at the Nintendo "hotline" in Norway back in the 1990s. These were given to them by Unsaco (now Bergsala), the official distributor of Nintendo games and merchandise in Norway, and were used to be able to give feedback on certain aspects of the game.

The game itself looks pretty close to the final version that was released only in Spain and Italy. A lot of the differences in the binary are related to blank areas in the memory. I did a side-by-side play of the prototype and final versions, and didn't notice anything majorly different as far as gameplay. I only really noticed a small change to the text in the in-game storyline.